From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D69C1C433EF for ; Thu, 24 Feb 2022 13:01:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234637AbiBXNCW (ORCPT ); Thu, 24 Feb 2022 08:02:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233821AbiBXNCV (ORCPT ); Thu, 24 Feb 2022 08:02:21 -0500 Received: from p3plsmtpa12-07.prod.phx3.secureserver.net (p3plsmtpa12-07.prod.phx3.secureserver.net [68.178.252.236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07B57329BC for ; Thu, 24 Feb 2022 05:01:50 -0800 (PST) Received: from localhost ([82.17.115.212]) by :SMTPAUTH: with ESMTPA id NDkinwwSF4g5nNDkjnn3CQ; Thu, 24 Feb 2022 06:01:50 -0700 X-CMAE-Analysis: v=2.4 cv=FvbAQ0nq c=1 sm=1 tr=0 ts=621781be a=9gipVNR6X1CoIeAWHwLoWw==:117 a=9gipVNR6X1CoIeAWHwLoWw==:17 a=IkcTkHD0fZMA:10 a=1lnWF7C_TSq6DCnCXLMA:9 a=QEXdDO2ut3YA:10 X-SECURESERVER-ACCT: atomlin@atomlin.com Date: Thu, 24 Feb 2022 13:01:48 +0000 From: Aaron Tomlin To: Marcelo Tosatti Cc: Frederic Weisbecker , Christoph Lameter , tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Phil Auld Subject: Re: [RFC PATCH] tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too Message-ID: <20220224130148.xfpfmybrtayjncor@ava.usersys.com> References: <20220203214339.1889971-1-atomlin@redhat.com> <20220217124729.GA743618@lothringen> <20220217142615.xqtiydixvnumyvei@ava.usersys.com> <20220217163205.GA748087@lothringen> <20220218125454.utlgmuhijklzr3if@ava.usersys.com> <20220219154616.pwsvh445x3vn7ltf@ava.usersys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-CMAE-Envelope: MS4xfFBGZKM6OSunN06Tbm0Ztuibn0pwdeWrky4QSfM+VrazJuNvuSs6abyyBknpFpM+JZ6MJsNyGCzM4n2izYj9SjYxwtwkrIW71V7FVHu00c03zcm6oCB2 9jhyX1Qvrp17MncCXR8QXvHhgKcb0InD5siT1lafNsWD4zN8/aOUD2TZkJgLnRW10jyiUcco3NftAHFOYuS20v1IuKQeWtw6iZAIsfGxUdXA5dpsBXLwPSr1 518IyejJKIrzmiuoGw/iRvQ26lrwEbAONLZ2AEjDF9aRE7QaLJZU8A4JSN3YhOu2m1rr1fUd8w8t9xms1a4zyYMzTPYHAoxikCBImzZnCYzWr14J3rmbPxmV j+6tzaGQdjvzQ2seksPBcRLZAvAjmDVH2eMcS5Gb3J1/3o0nUBw= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 2022-02-24 09:30 -0300, Marcelo Tosatti wrote: > > > > > 2) What if we are running task A in kernel mode while the tick is stopped > > > > > (nohz_full). Task A modifies the vmstat and goes to userspace for a long > > > > > while. > > > > > Your patch fixes case 1) but not case 2). The problem is that TIMER_DEFERRABLE > > > > > should really be about dynticks-idle only and not dynticks-full. I've always > > > > > been afraid about enforcing that rule though because that would break old > > > > > noise-free setups. But perhaps I should... > > Can't grasp the sentence above "The problem is that ...". > What rule? Hi Marcelo, That statement was from Frederic. Kind regards, -- Aaron Tomlin